1. Field of the Invention
The present general inventive concept relates to a hybrid inkjet image forming apparatus having a replaceable scanning unit and a replaceable inkjet head, and more particularly, to a hybrid inkjet image forming apparatus that can replace one of different inkjet head units of different types with a scanning unit.
2. Description of the Related Art
Generally, image forming apparatuses, such as printers, photo printers, copiers, fax machines, and digital multi-function products, are used to print images or documents on printing media. Printers are the most representative devices of the image forming apparatuses.
Inkjet printers form an image having a predetermined color on a surface of a printing medium, such as a sheet of paper or a sheet of fabric, by firing ink droplets onto a desired region of the printing medium. The inkjet printer includes an inkjet head that fires ink generally using a heater, a piezoelectric unit, or the like.
A conventional inkjet printer usually includes an inkjet head that prints an image on a printing medium such as paper while the inkjet head reciprocates in a direction perpendicular to a feeding direction of the paper, that is, a width direction of the paper. This inkjet head is called a shuttle type inkjet head, and an inkjet printer with the shuttle type inkjet head is called a shuttle type inkjet printer. However, since the shuttle type inkjet head reciprocates for printing, the conventional shuttle type inkjet printer has a low printing speed although it has high resolution.
A recently developed inkjet printer employs an inkjet head array arranged across the entire width of a printing medium, and rapidly printing an image on a feeding printing medium without a reciprocating motion of the inkjet head. This inkjet printer is called an array type inkjet printer. However, the array type inkjet printer, although suitable for high-speed printing, is not suitable for high-quality printing.
To obviate such problems of the shuttle type inkjet printer and the array type inkjet printer, a hybrid inkjet printer has been disclosed in U.S. Pat. No. 5,710,582. This hybrid inkjet printer includes a shuttle type inkjet head and an array type inkjet head placed in parallel, and selectively uses the inkjet heads in accordance with a user's demand. For example, when it is necessary to print a document (mostly, a black and white document) with high speed, the array type inkjet head is used, and when it is necessary to print a document (mostly, a color document) with high resolution, the shuttle type inkjet head is used.
However, in a case where the hybrid inkjet printer is employed for constructing a digital multi-function product having a scanner or copier function, a size of the digital multi-function product is likely to become bigger by adding a scanning unit above a printing part in the same way as in the conventional digital multi-function product. Further, the scanning unit requires a paper feeding path separate from that of the printing part, thereby further increasing a size and a manufacturing cost of the digital multi-function product.